The present invention relates to optimal width jewelry links For jewelry pieces, such as necklaces and the like.
In the jewelry industry the fabrication of chains, including rope chains, from individual C-shaped wire links is well known. The process is either manual or machine automated. The available technology can automatically form the wire links from a continuous supply of wire of a variety of crossectional shapes, such as round, square, or triangular.
However, the wire is bent around a mandrel and further formed with dies such that, except for round crossection wire, the C-shaped links always have a flat side that wraps around the mandrel, thus forming the inside diameter of a link to be formed from the wire.
This limits the width of the wire to the diameter of the cylindrical wire, or to the width of one edge of a square wire.
It is therefore a desirable object of the present invention to be able to form C-shaped jewelry links, from square crossectional wire, with a diamond shaped geometry, wherein an edge of the wire is wrapped around the mandrel, thus forming a C-shaped link whereby two distinct facet surfaces are visible from a top view.
Other objects which become apparent from the following description of the present invention.
In keeping with these objects and others, which may become apparent, the present invention includes machinery and a method for producing a wide C-shaped jewelry link, as well as the C-shaped link product produced thereby.
The crossection of the link-forming wire, which is orthogonal to the plane of the link, is then diamond shaped, with the widest points of the link corresponding to the wide common hypotenuse joining the two equilateral triangles, which forms the diamond cossectional width of the C-shaped link.
Thus the C-shaped links of the present invention appear to have been formed from a wire material having a width, which is 41% wider, than one wrapped from the same wire, using a flat surface against the forming mandrel. The C-shaped links thus formed also have two reflecting surfaces, when viewed from a top view.
To achieve this result, both the mandrel as well as the forming dies are grooved, in order to hold the square wire on one of its edges, during the wrapping and forming operations.
Although not absolutely essential, an optional spring-mounted mandrel is used to automatically pop off the finished C-shaped link from its alignment groove, prior to removal for further automated or manual assembly into the desired chain.
Many methods for dealing with the gap at the distal ends of a C-shaped link, as for prior art chains are applicable. One technique involves bonding two links together in pairs after they have engaged the desired number of other double link pairs.
Therefore, the present invention includes a method and a machine for forming a wide C-shaped link from a square wire having corners, forming a diamond shape when viewed in cross section, for use in making a jewelry chain. The machine includes a means for feeding the wire in and along a V-shaped groove formed in a surface of a stationary die, wherein the V-shaped groove is adapted to accommodate a first corner of the wire. The machine also includes a cutter for cutting the wire, to form a discrete wire section, with a predetermined length of the wire in the V-shaped groove, wherein the surface of the die has a concave forming surface between ends of the predetermined length of the wire.
The concave forming surface has a shape including a corner to correspond with the first corner of the wire in the V-shaped groove. A mandrel has a guidance groove matching a second corner of the wire, on an opposite side of the wire from the first corner, for pushing and bending the wire into the concave forming surface to form the wire into a U-shaped configuration. A pair of movable die sections close the wire, to form a C-shaped link surrounding the mandrel and the movable die sections have die V-shaped grooved surfaces, which are shaped to correspond to the first corner of the wire, thereby forming a C-shaped link of the wire, in which the second corner forms an inner circumference of the C-shaped link and the first corner forms an outer circumference of the C-shaped link.
The wire is square in cross section so that the C-shaped link is diamond-shaped, with optional facets, when viewed in crossection.
The wire may be a polygon, when viewed in crossection so that said C-shaped link is diamond shaped with facets.
The machine also includes an optional apparatus for removing a C-shaped link from a mandrel circular in crossection, the C-shaped link being in a groove surrounding the mandrel. This optional apparatus has a mandrel housing, having a blind hole in an end wall, to receive one end of the mandrel. This blind hole has a diameter, which is large enough to receive a first end of the mandrel, and which is not large enough to accommodate the C-shaped link on the mandrel. A pin is provided at right angles to a length of the mandrel for contacting an end of the mandrel within the hole, when the mandrel is inserted into the hole. A spring is provided within the hole, and it contacts a side of the pin, which is opposite to a side in contact with the first end of the mandrel. An anvil forces the first end of the mandrel against the pin compressing the spring, causing the end wall of the mandrel housing to pop the C-shaped link out of the groove in the mandrel. The spring at least partially ejects the mandrel from the blind hole when the anvil is retracted away from the mandrel.
A gripper mechanism is provided to remove the C-shaped link from a second end of the mandrel, after the C-shaped link is removed from the groove in the mandrel.
A length extending from the groove to the second end of the mandrel is sufficiently short as to allow the C-shaped link, when popped out of the groove in the mandrel, to drop into a container for collecting the C-shaped link.
In operation, a method is provided of making a jewelry chain from C-shaped links formed from a wire having corners in cross section, wherein the method comprises-the steps of:
a) feeding the wire in and along a V-shaped groove formed in a surface of a stationary die, the V-shaped groove being adapted to accommodate a first corner of the wire;
b) cutting the wire to form a predetermined length of the wire in the V-shaped groove, the surface of the die having a concave forming surface between ends of the predetermined length of the wire, the concave forming surface having a shape, including a corner, to correspond with the first corner of the wire in the V-shaped groove;
c) pushing and bending the wire into the concave forming surface, using a mandrel, having a guidance groove matching a second corner of the wire, on an opposite side of the wire from the first corner, to form the wire into a preliminary U-shaped configuration;
d) closing the wire to form a C-shaped link surrounding the mandrel, using a pair of movable die sections, the movable die sections having die V-shaped grooved surfaces, which are shaped to correspond to the first corner of the wire, thereby forming a C-shaped link of the wire, in which the second corner forms an inner circumference of the C-shaped link and the first corner forms an outer circumference of the C-shaped link;
e) removing the C-shaped link from the mandrel;
f) moving successive wire segments along the V-shaped groove formed in the surface of the stationary die to produce a plurality of C-shaped links from the same wire; and
g) combining the C-shaped links to form a jewelry chain.
The operation also includes a method of removing a C-shaped link from a mandrel, which is circular in cross section, wherein the C-shaped link is in a groove surrounding the mandrel, which removal operation includes the steps of:
a) inserting one end of the mandrel into a hole in an end wall of a mandrel housing, the hole having a diameter large enough to receive the mandrel and not large enough to accommodate the C-shaped link on the mandrel, wherein a pin is within the hole at right angles to a length of the mandrel for contacting an end of the mandrel within the hole, when the mandrel is inserted into the hole, and a spring is within the hole contacting a side of the pin opposite to a side in contact with the mandrel;
b) using an anvil to push the mandrel against the pin, compressing the spring and causing the end wall of the mandrel housing to pop the C-shaped link out of the groove in the mandrel, wherein the spring at least partially ejects the mandrel from the hole when the anvil is retracted; and
c) removing the C-shaped link from one end of the mandrel.
The method of the operation also includes removing the C-shaped link from the mandrel, by using a gripper, to grab the C-shaped link and moving the C-shaped link past an end of the mandrel.
Finally, the C-shaped link is removed from the mandrel by dropping off one end of the mandrel when the C-shaped link is popped out of the groove, which results in a fine jewelry link having a wide diamond-shaped crossection, without the need for expensive grinding or embossing to form the diamond-shaped configuration of the crossection of the formed C-shaped link.